Field of the Invention
The present invention relates to a lens apparatus used for optical apparatuses such as interchangeable lenses and image capturing apparatuses.
Description of the Related Art
In such a lens apparatus (lens barrel), multiple lens holders respectively holding lenses are installed while a relative shift of their optical axes (hereinafter referred to as “an optical axis shift”) are adjusted or corrected.
Japanese Patent Laid-Open No. 2006-058582 discloses a lens barrel in which a first lens holder is provided with a reinforcing plate attached thereto, the reinforcing plate is formed with paired walls extending in an optical axis direction and an eccentric pin is disposed between the paired walls and a second lens holder. This lens barrel allows, by rotating the eccentric pin, moving the second lens holder with respect to the first lens holder in a plane orthogonal to the optical axis direction and thereby correcting an optical axis shift of the first and second lens holders.
Japanese Patent Laid-Open No. 2007-011052 discloses a lens barrel in which an eccentric adjusting pin (eccentric cylindrical member) and a washer are arranged between first and second lens holders and are tightly sandwiched therebetween by screwing of fixing screws penetrating through the eccentric adjusting pin and the washer from a front side of the first lens holder in an optical axis direction. This lens barrel allows, by rotating the eccentric adjusting pin, moving the second lens holder with respect to the first lens holder in a plane orthogonal to the optical axis direction and thereby correcting an optical axis shift of the first and second lens holders. However, the lens barrel disclosed in Japanese Patent Laid-Open No. 2006-058582 requires the reinforcing plate in addition to the second lens holder, which results in an increase in total number of component parts. Moreover, this lens barrel requires fastening members, such as screws, disposed at other positions (phases) than that of the eccentric pin in a circumferential direction as viewed from the optical axis direction and used to fix the reinforcing plate to the first lens holder from the optical axis direction. This requirement results not only in a further increase in total number of the component parts, but also in, due to a large space occupied by the reinforcing plate, limitation in design flexibility of the lens barrel. On the other hand, the lens barrel disclosed in Japanese Patent Laid-Open No. 2007-011052 requires a large space in the optical axis direction because the eccentric adjusting pin, the washer and a head portion of the fixing screw are arranged such that they are stacked in the optical axis direction.
As described above, the lens barrel disclosed in Japanese Patent Laid-Open No. 2006-058582 requires providing, at other phases than that of the eccentric pin as viewed from the optical axis direction, the screws irrelevant to the correction of the optical axis shift. Moreover, the lens barrels disclosed in Japanese Patent Laid-Open Nos. 2006-058582 and 2007-011052 both require the screws extending in the optical axis direction. It is impossible to significantly shorten lengths of the screws from a fastening strength point of view, which restricts improvement of space efficiency.